<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<!--
1. 指数运算符(幂): **
2. Array.prototype.includes(value) : 判断数组中是否包含指定value

-->
<script type="text/javascript">
    console.log(3 ** 3);//27
    let arr = [1,2,3,4, 'abc'];
    console.log(arr.includes(2));//true
    console.log(arr.includes(5));//false
</script>
</body>
</html>